Hello,

what about other network activities? Do they drop the connection?

With IPTV connected to the main router, do you have the same issue? 

What is the IP address of IPTV when it lost connection?

Besides, did you try to move the powerline adapter into the same room where main router locates  to test the stability?

Below is the instruction to narrow down the issue, you can have a look.

https://www.tp-link.com/en/faq-2230.html

Good day.

Matic wrote

Hi, I have a problem with powerline adapters, when I watch TV over IPTV, the connection drop for 10 seconds, the middle powerline light blinks for 10 seconds, and then everything goes back to normal. This happens cca. every 30 minutes. What could be the problem?